Kanyanatt Kanokwiroon

Antimicrobial activity of a protein purified from the latex of Hevea brasiliensis on oral microorganisms

This study aimed at screen for antimicrobial activity present in the non‐rubber constituents of rubber latex of Hevea brasiliensis against various microbial strains. An antimicrobial protein, hevein was extracted from the bottom fraction after centrifugation and purified by acetone fractionation and anion exchange chromatography on a DEAE‐Sepharose Fast Flow column. This procedure was more efficient and rapid than the previously described procedures. The antimicrobial activity was investigated and revealed that hevein, a small (4.7 kDa) cysteine‐rich protein, had strong antimicrobial activity, especially against Candida spp. including Candida albicans, Candida tropicalis and Candida krusei. The MIC80 value for hevein was as low as 12 μg ml−1 with C. tropicalis ATCC 750. Higher MIC80 values were obtained for C. albicans ATCC 10231 (95 μg ml−1) and C. krusei ATCC 6258 (190 μg ml−1). To confirm the antifungal activity, hevein also inhibited the growth of those fungi in a disk diffusion assay and its inhibition was enhanced when a Hevea latex protease inhibitor was also included. Hevein at a concentration of 30 μg ml−1 also caused a Ca2+‐dependent aggregation of C. tropicalis yeast cells. These data indicate that hevein can inhibit the growth of certain potential oral fungal pathogens.

Effects of Kaempferia parviflora rhizomes dichloromethane extract on vascular functions in middle-aged male rat.

ETHNOPHARMACOLOGICAL RELEVANCE In Thai traditional medicine, rhizomes of Kaempferia parviflora (KP) have been used for treating hypertension and for the promotion of longevity with good health and well being. Ageing is one of the most important risk factors for development of cardiovascular disease. To investigate whether a 6 weeks oral administration of a dichloromethane extract of fresh rhizomes of Kaempferia parviflora (KPD) had any effects on vascular functions, on the accumulation of lipid, as well as on any signs of gross organ toxicity in middle-aged rats. MATERIALS AND METHODS Fresh rhizomes of Kaempferia parviflora were first macerated twice with 95% ethanol to remove the dark color before extracting three times with 100% dichloromethane. The dichloromethane extract was evaporated under reduced pressure to obtain the dried Kaempferia parviflora dichloromethane extract (KPD). The rats were orally administered with the KPD at a dosage of 100mg/kg body weight, or with the same volume of the vehicle (tween 80, 0.2g: carboxy-methylcellulose sodium, 0.2g: distilled water 10 ml) once or twice a day for 6 weeks. Vascular functions were studied on isolated thoracic aorta and the mesenteric artery. The vascular eNOS enzyme was measured by Western blot analysis. Blood chemistry was measured by enzymatic methods. Liver cell lipid accumulation was measured using oil red O staining. RESULTS A 6 weeks treatment of KPD once a day had no significant effects on any of the studied parameters. When the KPD was given twice a day, the contractile responses to phenylephrine of the thoracic aorta and mesenteric artery were lower than the vehicle control group, and this effect was abolished by N(G)-nitro-l-arginine or by removal of the vascular endothelium. Vasorelaxation to acetylcholine, but not to glyceryl trinitrate, by the thoracic aortic and mesenteric ring precontracted with phenylephrine was higher from the KPD treated rats than those from the vehicle control groups. Western blot analysis showed a higher quantity of thoracic- and mesenteric-eNOS protein obtained from the KPD treated rats. In addition, the body weight, serum glucose and triglycerides levels, visceral and subcutaneous fat, as well as liver lipid accumulation were all significantly decreased in the KPD treated rats compared to those of the vehicle control. No differences were found between the KPD treated-, and the vehicle-control for animal food intake, internal organ weight, serum ALP, SGOT, SGPT, BUN and creatinine levels, serum cholesterol, HDL-C and LDL-C levels, nor total blood cell counts. CONCLUSIONS The chronic oral administration of KPD extract, to middle aged rats, caused a decrease in vascular responsiveness to phenylephrine with an increase in the acetylcholine induced vasorelaxation, due to an increase in nitric oxide production from their blood vessels. The extract also caused a decrease in visceral and subcutaneous fat, fasting serum glucose and triglyceride levels and liver lipid accumulation, with no changes to liver and kidney functions or to total blood cell counts. It is possible that these KPD extracts could be developed as a health product for mid-aged humans to reduce obesity, diabetes type II and cardiovascular disease.

Effects of 6 weeks oral administration of Phyllanthus acidus leaf water extract on the vascular functions of middle-aged male rats.

ETHNOPHARMACOLOGICAL RELEVANCE Leaves of Phyllanthus acidus (PA) have been used in Thai traditional medicine for the treatment of hypertension. We have previously shown that chronic treatment of a PA water extract to middle-aged male rats caused a lowering of the body and serum lipids, two of the parameters that are implicated in cardiovascular disease. AIM OF THE STUDY To investigate if chronic treatment of middle-aged male rats with a PA water extract affected the perivascular (aortic) adipose tissue (PVAT) and/or their vascular functions MATERIALS AND METHODS Fresh leaves of PA were extracted with water and orally gavaged to the middle-aged male rats for 6 weeks. Vascular functions were studied in vitro using isolated thoracic aorta with and without PVAT, and mesenteric rings in Krebs Heinseleit solution with results recorded with a Polygraph or a Myograph system. The amount of blood vessel eNOS and CSE (cystathionine-γ-lyase) expression was measured by Western blotting. RESULTS PA treatment caused a lower maximal contractile response to phenylephrine (Phe) of the endothelium-intact aortic ring than that of the control group. This effect was abolished by N(G)-nitro-l-arginine (l-NA) or by denudation of the endothelium. dl-propargylglycine (PAG, H2S inhibitor) and TEA (Ca(2+)-activated K(+) channel blocker), but not glybenclamide (ATP-activated K(+) channel blocker), caused a similar increase in the baseline of the endothelium-intact aortic ring in the presence of l-NA in both the PA-treated and control aortic rings. This effect sequentially resulted in a greater contractile response of the aortic rings of both groups to Phe. Glybenclamide also caused a similar increase in the maximal contraction of the endothelium-intact blood vessels with l-NA to both groups. PAG, TEA or glybenclamide did not modify the phenylephrine C-R curves for either group of the PVAT-endothelium-intact aortic rings preincubated with l-NA. The CSE levels of the thoracic aorta and at the PVAT were not different between the PA-treated and the control group. Relaxation of the Phe-precontracted thoracic aortic ring to acetylcholine, but not to glyceryl trinitrate, was higher for the PA-treated than for the control aortic rings and this effect was abolished by l-NA. The mesenteric rings of the PA treated group showed a lower sensitivity on the contractile response to Phe than that of the control group, and this effect was abolished by l-NA. Vasodilatation to acetylcholine, but not to glyceryl trinitrate, of the PA treated-mesenteric ring was more sensitive than that of the control group and this effect was abolished by l-NA. The expression of eNOS by the PA treated thoracic aorta and the mesenteric arteries was higher than the control group. These results demonstrated that chronic treatment with a PA water extract to middle-aged rats affected their vascular functions by increasing the nitric oxide production from the endothelial cells and also modulated the responsiveness of the thoracic aortic- and mesenteric rings to phenylephrine and acetylcholine.

The dose dependent in vitro responses of MCF-7 and MDA-MB-231 cell lines to extracts of Vatica diospyroides symington type SS fruit include effects on mode of cell death

Background: Vatica diospyroides type LS is a known source of valuable compounds for cancer treatment, however, in contrast little is known about therapeutic efficacy of type SS. Objective: This study focused on in vitro cytotoxicity of these fruit extracts, and the cell death mode they induce in breast cancer cells. Materials and Methods: Acetone extracts of fruit were tested for cytotoxicity against MCF-7 and MDA-MB-231 cell lines. The apoptosis and necrosis of these cells were quantified by fluorescence activated cell sorter (FACS) and western blot analyses. Results: After 72 h of treatment, the 50% growth inhibition concentrations (IC50) levels were 16.21 ± 0.13 µg/mL against MCF-7 and 30.0 ± 4.30 µg/mL against MDA-MB-231, indicating high and moderate cytotoxicity, respectively. From the FACS results, we estimate that the cotyledon extract at half IC50 produced 11.7% dead MCF-7 cells via apoptosis, whereas another concentrations both apoptosis and necrosis modes co-existed in a dose-dependent manner. In MDA-MB-231 cell line, only the apoptosis was induced by the pericarp extract in a dose-dependent manner. With the extracts at half IC50 concentration, in both cells, the expression of p21 decreased while that of Bax increased within 12–48 h of dosing, confirming apoptosis induced by time-dependent responses. Apoptosis dependent on p53 was found in MCF-7, whereas the mutant p53 of MDA-MB-231 cells was expressed. Conclusion: The results indicate that fruit extracts of V. diospyroides have cytotoxic effects against MCF-7 and MDA-MB-231 cells via apoptosis pathway in a dose-dependent manner. This suggests that the extracts could provide active ingredients for the development, targeting breast cancer therapy.

Extracts from Vatica diospyroides Type SS Fruit Show Low Dose Activity against MDA-MB-468 Breast Cancer Cell-Line via Apoptotic Action

Very strong antiproliferative action of V. diospyroides type SS fruit extracts (IC50 range of 1.60-17.45 µg/mL) in MDA-MB-468 cell-line was observed in an MTT assay. After dosing of an extract concentration at half IC50 to cell line for 24 to 72 hours, treated cells were subjected to Annexin V-FITC/PI binding assay, followed by FACS and western blot analyses. Significant apoptotic death was observed with all extract treatments and both exposure times. Dosing with acetone extract of pericarp and cotyledon induced the highest apoptotic populations (33 and 32%, resp.), with the lowest populations of viable cells (65 and 67%, resp.). During 24 to 72 hours of dosing with methanolic extract of pericarp, the populations of viable and early apoptotic cells decreased significantly from 72.40 to 71.32% and from 12.00 to 6.36%, respectively, while the late apoptotic and nonviable cell populations continuously increased from 15.30 to 19.18% and from 0.30 to 3.14%, respectively. The expression of Bax increased within 12–48 hours of dosing, confirming apoptosis induced by time-dependent responses. The mutant p53 of MDA-MB-468 cells was expressed. Our results indicate that apoptosis and time-dependent therapeutic actions contribute to the cytotoxic effects of V. diospyroides type SS fruit on MDA-MB-468 cell.

Response of cardiac endothelial nitric oxide synthase to plasma viscosity modulation in acute isovolemic hemodilution

Background: Endothelial nitric oxide synthase (eNOS) is generally expressed in endocardial cells, vascular endothelial cells and ventricular myocytes. However, there is no experimental study elucidating the relationship between cardiac eNOS expression and elevated plasma viscosity in low oxygen delivery pathological conditions such as hemorrhagic shock-resuscitation and hemodilution. This study tested the hypothesis that elevated plasma viscosity increases cardiac eNOS expression in a hemodilution model, leading to positive effects on cardiac performance. Materials and Methods: Two groups of golden Syrian hamster underwent an acute isovolemic hemodilution where 40% of blood volume was exchanged with 2% (low-viscogenic plasma expander [LVPE]) or 6% (high-viscogenic plasma expander [HVPE]) of dextran 2000 kDa. In control group, experiment was performed without hemodilution. All groups were performed in awake condition. Experimental parameters, i.e., mean arterial blood pressure (MAP), heart rate, hematocrit, blood gas content and viscosity, were measured. The eNOS expression was evaluated by eNOS Western blot analysis. Results: After hemodilution, MAP decreased to 72% and 93% of baseline in the LVPE and HVPE, respectively. Furthermore, pO 2 in the LVPE group increased highest among the groups. Plasma viscosity in the HVPE group was significantly higher than that in control and LVPE groups. The expression of eNOS in the HVPE group showed higher intensity compared to other groups, especially compared with the control group. Conclusion: Our results demonstrated that cardiac eNOS has responded to plasma viscosity modulation with HVPE and LVPE. This particularly supports the previous studies that revealed the positive effects on cardiac function in animals hemodiluted with HVPE.